Spin Rate Breakdown

The Total Spin metric is total rpm of the ball. pitchLogic shows the Total Spin and also breaks it down into three components: backspin, sidespin and rifle spin. You may question how a ball can spin in three different directions at the same time. In truth, it is all one spin, but if we break it down mathematically, we can gain insight into how the spin axis can be controlled.

Backspin (and Top Spin) is the component of your total spin that generates vertical breaking force. The more Back Spin you have in a pitch, the more upwards lift force is on the ball. This means that the drop due to gravity is being counteracted and the trajectory of the pitch is flatter. If the vertical component of spin is in the opposite direction, aka Top Spin, the lift force will be downwards and cause the ball to have an increased break. Top Spin is the major component of a curveball.

Side Spin is the component that generates horizontal breaking force. The greater your Side Spin, the more break you will see to the right or the left.

The final component of Total Spin is the Rifle Spin, which is similar to the spiral spin of a football. Rifle Spin does not contribute to the breaking force of your pitch in any direction and, in general, it is better to keep your Rifle Spin value as small as possible. Even though it doesn’t contribute to the breaking force, Rifle Spin is a very important diagnostic tool, especially when you are learning a new pitch. Often when a new pitch, like a curveball, isn’t working, the pitcher will just throw more and harder, hoping for a better result. However, the underlying problem is often that the spin axis is incorrect and most of the spin motion is going into the Rifle Spin axis. If you are trying to throw a curve ball or other breaking ball, keep an eye on your Rifle Spin numbers. If they get too high, you may want to revisit your throwing motion with your coach rather than just throwing more and harder.

Let’s take a look at how all of this works in practice with a fastball example. The fastball uses Back Spin to counteract gravity, which gives it a flatter trajectory because gravity is being counteracted by the upwards lift force. Also, for maximum speed, a pitcher should minimize the Side Spin and Rifle Spin values. If you keep those values as small as possible, you are using your fingertips to push at the center of the ball during release which will maximize speed.

Consider the following fastball:

 
App Face Temp Horizontal_USE.png
 

Even though the Spin Direction (blue arrow) is nearly vertical, the majority of the total spin rate is going into the Rifle Spin. This results in a loss of speed and a loss of Back Spin, so your trajectory is not a flat as it could be. Shifting your energy from Rifle Spin to Back Spin will create more upward lift for a flatter trajectory and may boost your speed. Take a look at an improved example.

Here is an example of a better attempt at a fastball. Note this pitch was thrown at a higher speed and spin rates in general, but most of the spin is in Back Spin.

 
App Face FB Horizontal.png
 

The curveball is different from the fast ball because you want to create Top Spin (the opposite of Back Spin) and some Side Spin. This causes the pitch to break down and away from a right-handed batter when thrown by a right-handed pitcher. It is fundamentally different than a fast ball because it uses Top Spin to make the ball dive downward much more rapidly than a fast ball. Take a look at this curve ball.

 
App Face SL Horizontal.png
 

This pitch is not a textbook curve ball because the Top Spin (-345) is still low relative to the Side Spin. More practice with pitchLogic will help the pitcher increase the Top Spin rate and get the blue arrow pointing closer to 7, or even 6 o’clock. As we mention elsewhere, a left-handed pitcher will strive for a blue arrow pointing to 5 o’clock to get a good curveball.

Ultimately, understanding your component spin rates gives you a new, unprecedented layer of information that you can use to diagnose what is happening with each pitch and what is needed to improve.

Please be careful and recognize that improper technique or excessive repetition can cause injury. Breaking balls practiced improperly have a greater opportunity for injury so always follow your coach’s advice about how to practice controlling your spin rates safely.